首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   52573篇
  免费   2115篇
  国内免费   30篇
  2020年   593篇
  2019年   748篇
  2018年   1075篇
  2017年   1068篇
  2016年   1132篇
  2015年   753篇
  2014年   935篇
  2013年   4605篇
  2012年   1669篇
  2011年   1822篇
  2010年   1065篇
  2009年   1086篇
  2008年   1649篇
  2007年   1634篇
  2006年   1444篇
  2005年   1304篇
  2004年   1279篇
  2003年   1153篇
  2002年   1194篇
  2001年   1757篇
  2000年   1657篇
  1999年   1274篇
  1998年   670篇
  1997年   578篇
  1996年   514篇
  1995年   519篇
  1994年   498篇
  1993年   515篇
  1992年   1015篇
  1991年   955篇
  1990年   941篇
  1989年   851篇
  1988年   812篇
  1987年   804篇
  1986年   806篇
  1985年   854篇
  1984年   673篇
  1983年   577篇
  1982年   472篇
  1979年   657篇
  1978年   491篇
  1976年   449篇
  1975年   591篇
  1974年   621篇
  1973年   595篇
  1972年   540篇
  1971年   473篇
  1968年   539篇
  1967年   540篇
  1966年   477篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
Gay marriages (as such) are not as yet allowed anywhere but the demand for them is increasing. Most countries take a liberal attitude towards marriage: few obstacles are put in its way. But objections to gay marriages continue to be raised. These objections are refuted and the case for gay marriage is assessed through the prism of various forms of liberalism. The normative argument for allowing gay marriage is shown to be both strong and consistent with many of the values upheld by the opponents of such unions.  相似文献   
33.
In three experiments we studied the relationship between contextual conditioning and the reinstatement of extinguished lever pressing that occurs when noncontingent food is introduced following extinction. In all three experiments the non-contingent food was presented off-baseline (with the response levers not present). On subsequent tests, with the response levers present, animals that had been exposed to food showed more reinstatement of lever pressing than control animals. This finding rules out alternative mechanisms for the reinstated responding that rely on the interaction of non-contingent food and responding, such as superstitious reinforcement or the discriminative after-effects of food. In addition, in each experiment we demonstrated that manipulations known to affect contextual conditioning (signalling the food in Experiment 1, context extinction in Experiment 2, and switching contexts in Experiment 3) reduced the reinstatement. These results are consistent with the claim that contextual conditioning is important in controlling instrumental conditioning and closely parallel findings concerning the reinstatement of Pavlovian responsing following extinction.  相似文献   
34.
35.
A series of four spatial localization experiments is reported that examined the effects of display duration and presentation mode on positive and negative priming using an attended-repetition and an ignored-repetition paradigm, respectively. Experiment 1 showed larger positive priming with response-dependent than with 150 ms display durations while negative priming remained unaffected. Experiments 2-4 were performed to further elucidate the effects of prime-probe durations. Data suggest largely independent effects of prime and probe duration on priming effects. Manipulation of prime duration affected facilitation due to repetition of the prime distractor location as well as inhibitory effects associated with ignored repetition. Furthermore, anticipated probe duration modulated the effectiveness of inhibition of return. Findings are discussed within a framework proposing two major components of priming effects—a stimulus-driven or automatic component, and a strategic component related to the participant's expectations towards the probe.  相似文献   
36.
The authors used recursive partitioning methods to identify combinations of baseline characteristics that predict 2-year physical activity success in each of 3 physical activity interventions delivered in the multisite Activity Counseling Trial. The sample consisted of 874 initially sedentary primary care patients, ages 35-75 years, who were at risk for cardiovascular disease. Predictors of 2-year success were specific to each intervention and represented a range of domains, including physiological, demographic, psychosocial, health-related, and environmental variables. The results indicate how specific patient subgroups (e.g., obese, unfit individuals; high-income individuals in stable health) may respond differently to varying levels and amounts of professional assistance and support. The methods used provide a practical first step toward identifying clinically meaningful patient subgroups for further systematic investigation.  相似文献   
37.
38.
39.
40.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号